University of California, Berkeley
11/2003 -
10/2008
(CAN 3)

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BIOspheres of Mars: Ancient and Recent Studies

Overview

Mars is an exciting, and comparatively accessible target for astrobiological studies aimed at detection of current or past extraterrestrial life. We will analyze the evolution of the Martian hydrosphere and surface topography to understand the history of water distribution and investigate atmospheric processes that may have contributed to a UV shield. Our goal is to identify the types of sites on Mars that experienced long-term fluid flow and may be, or have been, conducive to life. We will characterize biomes that develop in analogous Earth environments, conduct experiments to determine limitations for life in these habitats, and identify features that constitute indicators of life. We propose robot-based sampling and in situ analyses of terrestrial sites so as to develop methods for dealing with the challenges of remote geomicrobiological investigations. Our work will provide constraints for selection of optimal sites for future Mars exploration and methods for sample analysis, and ultimately will be relevant to the question 'did life evolve elsewhere in the universe’.

Habitat Constraints from Mars and Modeling

Early microbial life probably originated on Earth in environments characterized by redox disequilibria. Habitats may have developed on Mars in redox gradients between reduced basaltic rocks and oxidized fluids and/or gases. Element cycling driven by fluid flow through such redox gradients could underpin (or could have underpinned) a substantial biosphere. We will analyze Mars planetary evolution to develop models for the timing and scale of hydrosphere development and subsurface water circulation. We will couple these hydrosphere models to geomorphological models based on terrestrial field site analyses and experimental geomorphological studies to allow detailed interpretation of Mars surface features. This will permit analysis of the history, form, and timing of fluid flow events that shaped the planetary surface and determination of the factors that control them. In parallel, we will explore atmospheric processes that could have contributed to a UV shield and conduct spectroscopic studies to constrain Mars surface mineralogy.

Habitat Constraints from Earth

Studies of chemoautotrophically-based ecosystems will focus on terrestrial aqueous environments in basaltic rocks similar to those at the Martian surface. Hydrology, geomorphology, spectroscopy, and geomicrobiology research will begin at sites where groundwater discharge in basaltic andesites or basalts is generating channels with features similar to those on Mars. These springs appear to offer the best chance of sustained water flow and protection from UV radiation. Initially, our studies will be conducted at cold and warm springs associated with basaltic rocks in dry, cold desert environments in Oregon and Idaho. We will refine our choice of study sites as our understanding of Mars’ surface improves.

Abundant, redox-active species such as iron and sulfur represent potential energy sources for possible Martian life at springs in basaltic rocks. Recent microbiological studies, geochemical calculations, and experiments indicate that the kinetics of both Fe-silicate and Fe-sulfide mineral dissolution reactions are fast enough to sustain significant biological populations. We will characterize currently poorly understood microbial habitats in the near subsurface in terms of their population structure, aqueous geochemistry, mineralogy, and isotopic signatures in order to determine the form of the record life might leave in similar Martian systems.

Laboratory Constraints for Habitat Development and Biosignatures

Results of in situ analyses of terrestrial ecosystems will be paralleled by laboratory-based studies that will explore the ranges of temperature, concentration, and pH consistent with life in the these habitats. Biochemical analyses will explore the factors that set these limits. We will analyze the structure, elemental and isotopic composition, microstructure, morphology, and distribution of minerals generated by, or impacted by, life in basaltic-rock hosted systems so as to develop and test potential new biosignatures. Parallel inorganic experiments will be conducted in order to resolve non-biological features and to examine changes in mineralogical biosignatures with time. As yet unstudied isotopic characteristics of Martian meteorites will be determined in order to provide baselines for isotopic biosignatures. Similarly, work on the isotopic evolution of the atmosphere will establish the magnitude and form of non-biological isotope fractionations. Application of state-of-the-art methods for analysis of Martian, and Mars-like rocks will yield procedures that will be useful for future analysis of samples returned to Earth or encountered during remote analysis on the Martian surface. Our results will contribute to selection of sites on the Martian surface with the highest potential for future detailed in situ investigations.

Our Team

Our goal is to create a highly interactive, focused NAI team to address a well-defined set of problems. The necessary interactions will be facilitated by close geographic proximity of most team members. Five of the 10 scientific team members are at UC Berkeley, one is at NASA Ames, and one in Palo Alto. The three other PIs have essential expertise for study of difficult to cultivate Fe-oxidizing neutrophiles and in situ measurements. All three non-Bay area coPIs have collaborated with the PI on a NASA-funded seed project preliminary to this proposal. Communication between all PIs will be promoted through work on common sites and processes, shared goals, and virtual (internet-based conferencing) and traditional group meetings.

Our group includes members with strong, integrated field and laboratory-based research programs and experience with study of a diversity of natural environments. Several team members are expert in the development and deployment of state-of-the-art analytical methods (e.g., isotopic analyses, microsensor measurements) to interdisciplinary problems. Our group also includes a robotics engineer and scientists familiar with ancient and recent Mars planetary history. The NAI support will be essential to facilitate the new interactions between hydrologists, geomorphologists, geomicrobiologists, chemists and engineers that are needed to meet the project goals.

Education and Public Outreach

The topics of life on Mars, life in extreme environments, and extraterrestrial exploration easily capture public attention. Our group will use the broad appeal of these subjects to create educational materials designed to foster interest in science, especially geology, chemistry, and biology. Educators from the University of California Berkeley’s Lawrence Hall of Science (LHS) will work closely with the BIOMARS team to develop, field-test, and implement materials that incorporate key project concepts and emphasize the interdisciplinary nature of space exploration. LHS is a public science center that is world-renowned for development of high quality middle and high school science curriculum materials based on current research and understanding of how students think and learn. Educational materials will be disseminated through the use of the LHS infrastructure, and its well-established national and international network of educators.